Speed changing device



Nov. 5, 1940- P. RAVIGNEAUX SPEED CHANGING DEVICE Filed Aug. 22. 1936 PMKavl neau \NVENTOQ I Patented Nov. 5, 1940 UNITED STATES PATENT OFFICE-Application August 22, 1936, Serial No. 97,377 In France August 27, 193513 Claims.

The present invention relates to speed changing devices for motorvehicles or any other mechanism.

One object of the invention is to provide a speed changing deviceembodying a smaller number of pinions than any other speed changingdevice known heretofore.

Another object is to provide a speed changing device affording the mostsuitable arrangement of speed ratios for the transmission of the energyof a vehicle engine to the driving wheels thereof.

A still further object is to provide a speed changing device wherein allforward speeds are obtained without disconnecting the gear members whichare connected with the driving shaft and the driven shaft from therespective shafts, the change of speed being simply provided by lockingintermediate members of said gear by means of non-rotary brakes.

A still further object is to devise a speed changing device comprisingtwo epicycloidal gears, each of which being so constructed that thefirst and last member thereof rotate in contrary directions 25 (negativespeed ratio) when the member supporting the planetary pinions is lockedagainst rotation, said epicycloidal gears having five concentric rotarymembers only for a speed box afiording four speed ratios in forwarddrive.

A still further object is to provide a speed changing device wherein theparts are so arranged that the members to be held stationary can bereached when the driven shaft is in line with the driving shaft; thiscondition is necessary for a considerable number of uses, and chieflyfor motor car frames in which the engine is in front and the drivingwheels in the rear.

In the accompanying drawing, which is given by way of example:

Figs. 1 and 2 are respectively a longitudinal section (on 2 o 3! Fig. 2)and a diagram relating to an embodiment using spur gears, with internal.tooth rings, in the case in which the rotation is to be transmitted toa shaft which is in line with 5 the driving shaft.

Fig. 3 shows a modification of Fig. 1, in which the central wheels andthe planetary pinions have the same diameter two by two.

Fig. 4 is a partial longitudinal section of a mod- 50 ificationaflording two reduced speeds, one on direct drive, one at an increasedratio and one on back drive.

Fig. 5, corresponding to Fig. 4, shows the connections to be made inorder to obtain the back drive by achangeof the driven part. 6

In the following examples, a single set of planetary pinions, onlyrepresented in the drawing, will be mentioned but, obviously, for thebalancing of the masses and forces, several sets of suitably arrangedpinions may be provided. 10

Figs. 1 to 3 relate to a speed changing device providing for fourspeeds, of which three speeds have a reduced ratio, and eventually adirect drive and back drive.

It comprises two epicycloidal gear sets with spur gears, each gear sethaving three wheels, i. e.,

a central wheel m or c with external teeth, a planetary pinion a or awith single teeth, and an internal tooth wheel b or r, making six wheelsin all. The four wheels m c b 1' are coaxial, as well as the support Aof the axles g g of the planetary pinions a 11 This device forms thefive parts of a complex epicycloidal gear set.

It should be noted that the two gear sets are such that the support Abeing fixed, the coaxial gear wheels of the same gear set have speeds inthe contrary direction, i. e., the gear set has a negative geometricalratio.

One of the planetary pinions (for instance a has a sufficient length toengage the planetary pinion a of the other gear set,

The first set of the mechanism shown in Fig. 1 comprises a central wheelm, a planetary pinion a mounted on an axle g pertaining to the supportA, which can be held stationary in order to obtain the first speed, andan internal tooth ring b which can be held stationary in order to obtain1 issituated on the side farthest from in motor with reference to thewheel c.

On the other hand, owing to a particular ar- .16 which, in order toconnect the wheels m and b,

passes by the teeth of the wheel and of the wheel r without touchingthese, is one of the essential features of the invention, in the case inwhich it is desired to transmit three reduced In order to obtain theback drive, various methods can be used, and in particular, one 7 canchange the part of the set which receives the driving torque, If thedriving part M is congo nected with the member C by the claws v winstead of connecting it with the part M by the claws 0 m this willafford, by holding stationary the part A, a back drive the reductionratio of which will be (-0.24). g; It will be noted that in thismechanical device which provides for three reduced speeds and directdrive, in the case in which the driven shaft is in line with the drivingshaft, the gearing will occupy, in all, three widths of wheels, and six30 gear wheels will suffice for all the combinations.

I In order to provide for certain speed ratios, it may be necessary touse a planetary pining 11. whose diameter is too great to allow it topass between the wheels 0 and r without touching them,

as and in this case it is possible, while still remaining within thelimits of the invention, to double this planetary pinion, for instanceby cutting it as shown in Fig. 3.

In this figure, the central wheels and the planetary pinions are madeequal in pairs, and this affords, for rings having for instance fourtimes as many teeth as the central wheels, the reduction ratios (+0.25)(+0.40) (+0.625).

By making c a driving part and by holding stationary the axles g and athis will afford a back drive with a reduction of (-0.25).

The frame carrying the axles of the planetary pinions has not beenrepresented.

Fig. 4 shows another modification, in which a the device again comprisesthe two epicycloidal gear sets, having negative geometrical ratios, eachof which comprises a central gear wheel with external teeth, I: or c, aninternal tooth ring (m or a) and a planetary pinion (a or a), theplanetary pinions with single teeth being mounted on the same frame Rand being in gear engagement with each other as shown by the diagram,Fig.

. 2. I In order to obtain two speeds at reduced ratios, a third, ondirect drive, and one at increased ratio, the connections for thedriving shaft and the driven shaft are made in a different manner fromwhat is shown in Fig. 1. The driving shaft is connected with theinternal tooth ring 112., and the driven shaft R is secured to thesupport R 55 for all forward speeds, and for the speeds on back dg'ive,it is secured to one of the central wheels The internal tooth ring a,the one that is not connected to the driving shaft, constitutes the 70part which is to be held stationary in order to obtain the first speed.The second speed is obtained by holding the central wheel b, and thefourth by holding the third central wheel e which is smaller.

7 A, B, C, indicate the parts to be held stationary for the three speedswhich are not direct.

starting from the slowest.

It should be noted that this device comprises only two widths ofgearing. By giving to'the wheels the following numbers 5 of teeth, whichare chosen by way of example:

m='l2 teeth It frame a =88 teeth 10 b =42 teeth 0 22 teeth a teeth =33teeth the speeds given below will be obtained; the first 15 column givesthe speed ratios of the driven shaft to the driving shaft, and thesecond, the ratio of the given speed of the driven shaft to the speedwhich it has at the fourth speed, the one which is increased.

1st speed 0.45 0.313 2nd speed 0.632 0.44

3rd speed 1. 0.695 4th speed 1.44 1.

If the back drive is obtained by using b as a driven part, and byholding a, the following ratios are obtained:

Back drive (-0.495 (-0.344)

Fifth speed: It should be noted that it is possible, without adding asingle piece to the mechanism represented, to obtain a flfth speed bymaking the part b a-driven part, as for the back drive, but the part cbeing braked.

The speed ratios to be added to the list are as follows It should beobserved that in the case of Fig. 4, it is quite feasible, as shown atJ, to place all the gear wheels in a casing in which they will beprotected against metallic particles which may result 'from the braking,and on the other hand, to permit employing braking means which operatein the dry state.

Fig. 5 shows a modified form employed for the back drive in theembodiment of Fig. 4.

The receiving shaft R which is normally coupled to the wheel R by clawsor by a friction clutch (for instance the cones e a) may be separatedfrom the same, and may be coupled to the wheel 17, for instance by meansof cones 2 s Obviously, the said invention is not limited to theembodiments herein described and represented, which are given solely byway of ex- 5 ample.

Thus it is feasible to employ indiscriminately and without departingfrom the limits of the invention, all methods for the securing ortheholding of the parts, such as clutching and braking of the disc typeclutching and braking of the magnetic type, or with expanding segments.7

The use of a tappet might be preceded, in order to connect two partstogether, or to stop one of these, by a friction device acting after themanner of the "synchromesh of speed changing boxes.

An arm provided with a tappet may for instance carry a. brake shoemounted on the same in an elastic manner and causing the slowing or thestopping of a. drum before the tappet comes into action.

In the following claims, when it is stated that 'the driven shaft is in.axial alignment with the driving shaft, it is meant thereby that said 15driven shaft is located in line with the driving shaft and that bothshafts could be made solid throughout without affecting th operatingfunctions of the assembly.

5 Having now described my invention what I claim as new anddesire tosecure by Letters Patent is:

1. A change speed gear comprising in combination a driving shaft and adriven shaft in axial alignment, a planetary assembly comprising fiveconcentric members, that is two sun wheels, two annuli and a pinioncarrier, and two satellite pinions meshing with each other and rotatablymounted on said pinion carrier, one of said pinions meshing with one sunwheel and one annulus and the other pinion meshing with the other sunwheel and the other annulus, one train consisting of one sun wheel, oneannulus and the pinion meshing with said sun wheel and annulus havingone at least of said three elements of a diameter difi'erent from thediameter of the corresponding element of the other train, two of saidcoaxial members being locked in rotation with said driving shaft andsaid driven shaft respectively, whereas the others are loose on theiraxis, and means adapted to selectively lock against rotation one of saidthree loose coaxial members.

2. A change speed gear according to claim 1, further comprising meansadapted to lock together two rotary members for direct drive.

3. A change speed gear realising at least one reduced forward speed andone reduced reverse speed comprising in combination a driving shaft,

a driven shaft, a planetary assembly comprising five concentric members,that is two sun wheels, two annuli and a pinion carrier, and twosatellite pinions meshing with each other and rotatably mounted on saidpinion carrier, one of said pinions meshing with one sun wheel and oneannulus and the other pinion meshing with the other sun wheel and theother annulus, and one of said coaxial members being secured to one ofsaid shafts, clutching means adapted to connect the other of said shaftswith any one of two coaxial members not secured to saidone of saidshafts, and means adapted to selectively lock against rotation one ofthe coaxial members not secured to either one of said shafts in suchmanner as to obtain in one position of said clutching means a reversedrive and in the other position at least one forward drive.

4. A changespeed gear according to claim 3 further comprising meansadapted to lock together two rotary members for direct drive.

5. A change speed gear comprising in combi nation a driving shaft, adriven shaft, a planetary assembly comprising five concentric members,that is two sun wheels, two annuli and a pinion carrier, and twosatellite pinions meshing with each other and rotatably mounted on saidpinion carrier, one of said pinionsmeshing with one sun wheel and oneannulus and the other pinion meshing with the other sun wheel 5 and theother annulus, and at least one of the satellite pinionsof one trainextending between and clearing the sun wheel and the annulus of theopposite train.

6. A change speed gear comprising in combi- 70 nation a. driving shaft,a driven shaft, a planetary assembly comprising five concentric members,that is two sun wheels, two annuli and a pinion carrier, and twosatellite pinions meshing with each other and rotatably mounted on 75said pinion carrier, one of said pinions meshing with one sun wheel andone annulus and the other pinion meshing with the other sun wheel andthe other annulus, the sun wheel and the annulus of one train beingrespectively on opposite sides of the sun wheel and the annulus of 5 theother train.

7. A change speed gear comprising in combination a driving shaft, adriven shaft, a planetary assembly comprising five econcentric members,that is two sun wheels, two annuli and a 10 pinion carrier, and twosatellite pinions meshing with each other and rotatably mounted on saidpinion carrier, one of said pinions meshing with one sun wheel and oneannulus and the other pinion meshing with the other sun wheel 15 and theother annulus, and the planetary pinion extending between the sun wheeland the annulus of one train having between two partsof the same gearsurface a reduced diameter small enough to clear the teeth of the sungear and 20 of the annulus of the other train.

8. A change speed gear comprising in combination a driving shaft, adriven shaft, a planetary assembly comprising five concentric members,that is two sun wheels, two annuli and a 25 pinion carrier, and twosatellite pinions meshing with each other and rotatably mounted on saidpinion carrier, one of said pinions meshing with one sun wheel and oneannulus and the other pinion meshing with the other sun 30 wheel and theother annulus, one of said shafts being locked in rotation with one ofsaid coaxial members, means for selectively connecting in rotation theother of said shafts with any one of two others of said concentricmembers, 35 means adapted to selectively lock against rotation one ofthe coaxial members not secured to either one of said shafts, thenumbers of teeth of the different wheels being selected in such manneras to obtain four forward speed ratios, 40 including direct drive, andat least one reduced reverse speed.

9. A change speed gear comprising in combination a driving shaft, adriven shaft, a planetary assembly comprising five concentric mem- 45bers, that is two sun wheels, two annuli and a pinion carrier, and twosatellite pinions meshing with each other and rotatably mounted on vsaidpinion carrier, one of said pinions meshing with one sun wheel and oneannulus and 50 the other pinion meshing with the other sun wheel and theother annulus, one of said shafts being locked in rotation with one ofsaid coaxial members, means for selectively connecting in rotation theother of said shafts with any 55 one of two others of said concentricmembers, means adapted to selectively lock against rotation one of thecoaxial members not secured to either one of said shafts, the numbers ofteeth of the diiferent wheels being selected in such 60 manner as toobtain at least two reduced forward speeds, one direct drive, oneoverdrive and at least one reduced reverse speed. I

10. A speed changing device affording at least four speeds in forwarddrive and one' reduced reverse speed comprising in combination a drivingshaft, a driven shaft, and two epicycloidal trains connecting saidshafts together and comprising for each train one externally toothed sungear, one internally toothed annulus and a sin gle planetary pinion, theplanetary pinion of one train being in constant mesh with the planetarypinion of the other train, a common rotary support for said planetarypinions, said sun gears, annuli and rotary support forming five rotaryof said first train being on the other side of the annulus of saidsecond train, the planetary pinion of said first train extending betweenthe sun wheel and the annulus of said second train and having at leastlocally such a small diameter as to clear the toothings of the sun gearand annulus of said second train, and the annulus of said second trainbeing constantly locked in rotation with said driven shaft, meansadapted to selectively lock against rotation the common support, theannulus of said first train and the sun wheel of said second train,clutching means adapted to connect said driving shaft selectively withthe sun wheel of said second train for reverse drive, the common supportbeing then locked against rotation, and with the sun wheel of said firsttrain for forward drive, the common support, the annulus of said firsttrain and the sun wheel of said second train being locked againstrotation respectively for the first, second and third forward reducedspeeds, and means for locking together said two sun wheels for directdrive.

11. A speed changing device affording two reduced speeds, a direct driveand an amplifled top speed in forward drive, comprising in combination adriving shaft, a driven shaft and two epicycloidal trains arranged sideby side, the first of said trains comprising an annulus locked inrotation with said driving shaft, a loose sun wheel and a planetarypinion, and the second train comprising a loose annulus, a loose sunwheel and a planetary pinion meshing with the planetary pinion of thefirst train, a common rotary support for said planetary pinions lockedin rotation with said driven shaft, means for selectively locking eitherof said sun wheels and said loose annulus against rotation, and meansfor locking together two of the rotary members of said device for directdrive.

12. A speed changing device as claimed in claim ll further comprisingmeans for disconnecting said rotary support from said driven shaft andmeans for connecting the latter with one of said sun wheels, for reversespeed.

13. A change speed gear comprising in combination a driving shaft, adriven shaft, a planetary assembly comprising five concentric members,that is two sunwheels, two annuli and a pinion carrier, and twosatellite pinions meshing with each other and rotatably mounted on saidpinion carrier, one of said pinions meshing with one sun wheel and oneannulus and the other pinion meshing with the other sun wheel andthe-other annulus, one of said shafts being locked in rotation with oneof said sun wheels and annuli, means for selectively connecting inrotation the other of said shafts with any one of two others of said sunwheels and annuli, and means adapted to selectively resist the motion ofone of the three coaxial members not secured to either one of saidshafts, the resisting means of the pinion carrier including a flangeextending between the two annuli.

POL RAVIGNEAUX.

